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S21 crashing/rebooting 1-2 times/day. Any tips on troubleshooting?

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dougleto

Member
Oct 13, 2011
26
1
I have as SM-G991U (256 GB S21 US version, stock everything but using Nova Launcher) that is randomly freezing/crashing then rebooting on me 1-2 times/day. Does android have any kind of crash log I could look at to try and figure out what's causing the problem? On the samsung forums, their support reps suggest running in Safe Mode, which I have, but it's not very useful because I can't reproduce the problem on demand and it usually happens 1-2/day, but sometimes less, so unless I just ran in safe mode all the time, that wouldn't tell me much. Plus, it would only tell me it's an issue caused by one of a hundred or so apps which, again, is not helpful.

So I'm hoping there is a crash log or something somewhere because I have no idea what triggers the crashes. The other night, it was sitting on a wireless charger, the screen wasn't on, then all the sudden it rebooted. It's not specific to any app or anything I'm doing. If there are no crash logs (which would be frustrating and disappointing), any other troubleshooting ideas are welcome!
 

blackhawk

Senior Member
Jun 23, 2020
5,624
1,664
Look for a memory leak. Typically a poorly written 3rd party apk.
Try clearing system cache.
Make sure auto restart isn't enabled...
 
I have as SM-G991U (256 GB S21 US version, stock everything but using Nova Launcher) that is randomly freezing/crashing then rebooting on me 1-2 times/day. Does android have any kind of crash log I could look at to try and figure out what's causing the problem? On the samsung forums, their support reps suggest running in Safe Mode, which I have, but it's not very useful because I can't reproduce the problem on demand and it usually happens 1-2/day, but sometimes less, so unless I just ran in safe mode all the time, that wouldn't tell me much. Plus, it would only tell me it's an issue caused by one of a hundred or so apps which, again, is not helpful.

So I'm hoping there is a crash log or something somewhere because I have no idea what triggers the crashes. The other night, it was sitting on a wireless charger, the screen wasn't on, then all the sudden it rebooted. It's not specific to any app or anything I'm doing. If there are no crash logs (which would be frustrating and disappointing), any other troubleshooting ideas are welcome!
Hi mate

For logs info check here and here

You can always flash firmware , using home_csc , to avoid factory reset the phone , if the problem is system related it will help

If is app related
Try booting in safe mode to see if problem goes away...
 

dougleto

Member
Oct 13, 2011
26
1
Hi mate

For logs info check here and here

You can always flash firmware , using home_csc , to avoid factory reset the phone , if the problem is system related it will help

If is app related
Try booting in safe mode to see if problem goes away...

Thanks! I'll definitely try these out. I tried safe mode, the trouble is it's not really great as a diagnostic because the phone will go from 4-24 hrs between resets during normal operation, and since a phone in safe mode isn't terribly useful, it's hard to keep it in safe mode for long enough to see if that fixed the issue, if that makes sense. And then, if it did fix the issue, it just narrows it down to 1 out of a hundred apps! But maybe I'm missing something. Is there additional information I can find if I run in safe mode that would help suss out the problem?
 

dougleto

Member
Oct 13, 2011
26
1
Look for a memory leak. Typically a poorly written 3rd party apk.
Try clearing system cache.
Make sure auto restart isn't enabled...
Thanks! I know how to clear cache but not how to check for memory leaks. Do you have a tool you'd recommend to do that? And I had never heard of auto restart before, so thanks for that. I confirmed that it is NOT enabled (that would have been a face palm moment!).
 
Thanks! I'll definitely try these out. I tried safe mode, the trouble is it's not really great as a diagnostic because the phone will go from 4-24 hrs between resets during normal operation, and since a phone in safe mode isn't terribly useful, it's hard to keep it in safe mode for long enough to see if that fixed the issue, if that makes sense. And then, if it did fix the issue, it just narrows it down to 1 out of a hundred apps! But maybe I'm missing something. Is there additional information I can find if I run in safe mode that would help suss out the problem?
Is not easy , you just need to be methodic

See if you can find anything useful in the logs first

Reflash firmware , use home-csc , see if it help

Have you notice if the phone fails under any specific circumstances?

If that does not help and if you can really relate the problem with any specific app you may try to freeze or uninstall suspicious app and let it run for a day , Package disabler app is a good option , it is easy to enable or disable app but is not free, you could try this one , is a debloater tool , it allow you to disable app... may be easy that having to uninstall / install by hand
 

GillBates21

Member
Sep 24, 2021
5
0
I'm also having the same problem. Had the phone since June, it didn't start to occur until late August, which leads me to suspect it is an update related issue.
 

dougleto

Member
Oct 13, 2011
26
1
I'm also having the same problem. Had the phone since June, it didn't start to occur until late August, which leads me to suspect it is an update related issue.
I'm glad you posted today, I've been meaning to post again here because I tried troubleshooting and am still having issues. In fact, it crashed twice today when I was trying to send a text message.

I installed one of the log applications (can't remember which one at the moment) but it wasn't really helpful. They didn't seem to catch any information related to a crash even though they were logging data at least twice when it crashed.

Then I tried reflashing using home-csc using ODIN and that ended up soft-bricking my phone (and yes, I followed all the instructions and used home-csc) so I had to reflash everything and do a full factory reset. That seemed to help, reducing the crashes from once/day to once/2-3 days for a few weeks, but now it's back to ~once a day (sometimes more, sometimes less).

So if anyone has any other idea, I'm all ears. When I was reflashing and stuff, I noticed in the recovery mode (or whatever it's called) options that you can look at logs. Does anyone know if one of those logs would have crash-related data or any other ideas of what to try? This is incredibly frustrating, especially that it's persisting after a factory reset. Argh!
 

GillBates21

Member
Sep 24, 2021
5
0
I'm glad you posted today, I've been meaning to post again here because I tried troubleshooting and am still having issues. In fact, it crashed twice today when I was trying to send a text message.

I installed one of the log applications (can't remember which one at the moment) but it wasn't really helpful. They didn't seem to catch any information related to a crash even though they were logging data at least twice when it crashed.

Then I tried reflashing using home-csc using ODIN and that ended up soft-bricking my phone (and yes, I followed all the instructions and used home-csc) so I had to reflash everything and do a full factory reset. That seemed to help, reducing the crashes from once/day to once/2-3 days for a few weeks, but now it's back to ~once a day (sometimes more, sometimes less).

So if anyone has any other idea, I'm all ears. When I was reflashing and stuff, I noticed in the recovery mode (or whatever it's called) options that you can look at logs. Does anyone know if one of those logs would have crash-related data or any other ideas of what to try? This is incredibly frustrating, especially that it's persisting after a factory reset. Argh!
So what I tried to do is roll back all the default google app updates. Ex: Android system webview, Google app itself, etc etc. I factory reset it without backing up any apps (but pictures and messages etc), It was working for a few days and then it happened again. Which further reinforces my thinking that my problem is software based.
 

dougleto

Member
Oct 13, 2011
26
1
So what I tried to do is roll back all the default google app updates. Ex: Android system webview, Google app itself, etc etc. I factory reset it without backing up any apps (but pictures and messages etc), It was working for a few days and then it happened again. Which further reinforces my thinking that my problem is software based.
So I'm curious why you think that means it's a software issue. If this isn't a widespread issue with the S21 and after we've both done a factory reset and still have the issue, that makes me think it could be a hardware issue. Of course, there could be some software incompatibility with an app that most people don't have installed or a bluetooth connection or something, which is why I really want to find a useful crash log (and find it rather absurb how hard it is to find a useful crash log on android, come on guys, it's a mature OS, some kind of crash log seems pretty basic!), because otherwise, it could be a ton of issues and I can't reproduce it. Ugh.
 

GillBates21

Member
Sep 24, 2021
5
0
The reason is that the "few days" after the reset and restoring pictures, messages (but not apps) from backup, where there were no crashes at all (where previously it would happen at least 2 times per day).
 

dougleto

Member
Oct 13, 2011
26
1
The reason is that the "few days" after the reset and restoring pictures, messages (but not apps) from backup, where there were no crashes at all (where previously it would happen at least 2 times per day).
Got it, that makes sense. I'm on t-mobile and just got an update this morning. We'll see if that improves anything because my device restarted 4 times yesterday
 

dougleto

Member
Oct 13, 2011
26
1
I havent had a crash like this since i disabled chrome and other google stuff, and downgrading google apps lol.
How did you disable chrome and what other google stuff did you disable? (There's obviously quite a lot of google services that can't be disabled)

After the most recent monthly update, my phone has gone from rebooting multiple times/day to once every 2-3 days, which is more manageable but still super annoying. It is incredibly frustrating to me that there are no good tools to troubleshoot a crash (at least that I've ben able to find). Honestly, it's driven me to consider an iPhone for the first time in my life :(.